Overview

Meninges

Meninges

Three layers of membranes known as meninges protect the brain and spinal cord. The delicate inner layer is the pia mater. The middle layer is the arachnoid, a web-like structure filled with fluid that cushions the brain. The tough outer layer is called the dura mater.

A meningioma is a tumor that arises from the meninges — the membranes that surround your brain and spinal cord. Although not technically a brain tumor, it is included in this category because it may compress or squeeze the adjacent brain, nerves and vessels. Meningioma is the most common type of tumor that forms in the head.

Most meningiomas grow very slowly, often over many years without causing symptoms. But in some instances, their effects on adjacent brain tissue, nerves or vessels may cause serious disability.

Meningiomas occur most commonly in women, and are often discovered at older ages, but a meningioma may occur at any age.

Because most meningiomas grow slowly, often without any significant signs and symptoms, they do not always require immediate treatment and may be monitored over time.

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